CacheFlare: Optimizing Cold Content Performance in CDNs

Abstract

Existing research on Content Delivery Networks (CDNs) predominantly focuses on optimizing the delivery of hot content—popular items that attract frequent and repeated access from large user bases. However, at Meta, we have identified that cold content, which is less popular and accessed infrequently, poses significant challenges for user experience, especially with large volumes of direct messaging media. Through extensive analysis of Meta's CDN data, we quantify the impact of cold content performance on user experience and reveal substantial differences across geographic regions. Motivated by these findings, we propose CacheFlare, a suite of production-deployed solutions designed to enhance Quality of Experience (QoE) by increasing CDN hit rates for cold content. Through experiments and production validation, we show that even cold content can benefit from improved caching strategies, yielding up to a 10% improvement across a range of network performance metrics.